Linux, specificaly Linux Mint. Been using a customized Win8 lately because I've been doing more gaming and it's just simpler than tweaking the games to work through Wine. Overall though Linux is my hands-down choice.

Mac or Linux..if can pick both of it.coz open source,cheap consider free.can run window on it's system.been test on my local PC fair or alike in Indonesia.hard to get hit by virus too.but..need few adjustedment bit.coz system not so commoned.

Windows XP Professional was wonderful. That's what I had on My Alienware Years ago. Yeah, yeah...I know all the detrimental Comments slung at Alienware Tech, AND even more so, toward those who Purchase the Machines. Meh, it was fun while it lasted; 9 Years and it feel into disrepair, mostly on the fault of My Own, rather than anything directed towards the Tech.